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<span>Anatomy</span> </div> </a> <ul id="toc-Anatomy-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Human_uses" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Human_uses"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Human uses</span> </div> </a> <button aria-controls="toc-Human_uses-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Human uses subsection</span> </button> <ul id="toc-Human_uses-sublist" class="vector-toc-list"> <li id="toc-As_incense_material" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#As_incense_material"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>As incense material</span> </div> </a> <ul id="toc-As_incense_material-sublist" class="vector-toc-list"> </ul> </li> <li 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class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Opercle_(gaster%C3%B2podes)" title="Opercle (gasteròpodes) – Catalan" lang="ca" hreflang="ca" data-title="Opercle (gasteròpodes)" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Operkulum" title="Operkulum – Czech" lang="cs" hreflang="cs" data-title="Operkulum" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Operculum" title="Operculum – German" lang="de" hreflang="de" data-title="Operculum" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%95%CF%80%CE%B9%CF%80%CF%89%CE%BC%CE%AC%CF%84%CE%B9%CE%BF_(%CE%B3%CE%B1%CF%83%CF%84%CE%B5%CF%81%CF%8C%CF%80%CE%BF%CE%B4%CE%B1)" title="Επιπωμάτιο (γαστερόποδα) – Greek" lang="el" hreflang="el" data-title="Επιπωμάτιο (γαστερόποδα)" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Op%C3%A9rculo_(gaster%C3%B3podos)" title="Opérculo (gasterópodos) – Spanish" lang="es" hreflang="es" data-title="Opérculo (gasterópodos)" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Opercule_(mollusque)" title="Opercule (mollusque) – French" lang="fr" hreflang="fr" data-title="Opercule (mollusque)" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Op%C3%A9rculo_(gaster%C3%B3podos)" title="Opérculo (gasterópodos) – Galician" lang="gl" hreflang="gl" data-title="Opérculo (gasterópodos)" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Opercolo" title="Opercolo – Italian" lang="it" hreflang="it" data-title="Opercolo" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Operkulas" title="Operkulas – Lithuanian" lang="lt" hreflang="lt" data-title="Operkulas" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Operculum_(mollusken)" title="Operculum (mollusken) – Dutch" lang="nl" hreflang="nl" data-title="Operculum (mollusken)" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Wieczko_(konchiologia)" title="Wieczko (konchiologia) – Polish" lang="pl" hreflang="pl" data-title="Wieczko (konchiologia)" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Op%C3%A9rculo_(gastr%C3%B3pode)" title="Opérculo (gastrópode) – Portuguese" lang="pt" hreflang="pt" data-title="Opérculo (gastrópode)" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9E%D0%BF%D0%B5%D1%80%D0%BA%D1%83%D0%BB%D1%83%D0%BC_(%D0%B1%D1%80%D1%8E%D1%85%D0%BE%D0%BD%D0%BE%D0%B3%D0%B8%D0%B5)" title="Оперкулум (брюхоногие) – Russian" lang="ru" hreflang="ru" data-title="Оперкулум (брюхоногие)" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-tl mw-list-item"><a href="https://tl.wikipedia.org/wiki/Unya" title="Unya – Tagalog" lang="tl" hreflang="tl" data-title="Unya" 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searchaux" style="display:none">Hard structure which closes the aperture of a gastropod when the animal retreats into the shell</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Lunella_(Ninella)_torquata_002.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Lunella_%28Ninella%29_torquata_002.jpg/220px-Lunella_%28Ninella%29_torquata_002.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Lunella_%28Ninella%29_torquata_002.jpg/330px-Lunella_%28Ninella%29_torquata_002.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Lunella_%28Ninella%29_torquata_002.jpg/440px-Lunella_%28Ninella%29_torquata_002.jpg 2x" data-file-width="1365" data-file-height="1024" /></a><figcaption>Shell of marine snail <i><a href="/wiki/Lunella_torquata" title="Lunella torquata">Lunella torquata</a></i> with the <a href="/wiki/Calcareous" title="Calcareous">calcareous</a> operculum in place</figcaption></figure> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Viviparus_contectus_met_operculum2.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Viviparus_contectus_met_operculum2.JPG/220px-Viviparus_contectus_met_operculum2.JPG" decoding="async" width="220" height="267" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Viviparus_contectus_met_operculum2.JPG/330px-Viviparus_contectus_met_operculum2.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Viviparus_contectus_met_operculum2.JPG/440px-Viviparus_contectus_met_operculum2.JPG 2x" data-file-width="506" data-file-height="614" /></a><figcaption><a href="/wiki/Gastropod_shell" title="Gastropod shell">Gastropod shell</a> of the freshwater snail <i><a href="/wiki/Viviparus_contectus" title="Viviparus contectus">Viviparus contectus</a></i> with corneous operculum in place</figcaption></figure> <p>The <b>operculum</b> (<a href="/wiki/Latin_language" class="mw-redirect" title="Latin language">Latin</a> for 'cover, covering'; <abbr title="plural form">pl.</abbr> <b>opercula</b> or <b>operculums</b>) is a <a href="/wiki/Corneous" title="Corneous">corneous</a> or <a href="/wiki/Calcareous" title="Calcareous">calcareous</a> anatomical structure like a <a href="/wiki/Trapdoor" title="Trapdoor">trapdoor</a> that exists in many (but not all) groups of <a href="/wiki/Sea_snail" title="Sea snail">sea snails</a> and <a href="/wiki/Freshwater_snail" title="Freshwater snail">freshwater snails</a>, and also in a few groups of <a href="/wiki/Land_snail" title="Land snail">land snails</a>; the structure is found in some marine and freshwater <a href="/wiki/Gastropod" class="mw-redirect" title="Gastropod">gastropods</a>, and in a minority of terrestrial gastropods, including the families <a href="/wiki/Helicinidae" title="Helicinidae">Helicinidae</a>, <a href="/wiki/Cyclophoridae" title="Cyclophoridae">Cyclophoridae</a>, <a href="/wiki/Aciculidae" title="Aciculidae">Aciculidae</a>, <a href="/wiki/Maizaniidae" title="Maizaniidae">Maizaniidae</a>, <a href="/wiki/Pomatiidae" title="Pomatiidae">Pomatiidae</a>, etc. </p><p>The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of "trapdoor" to close the <a href="/wiki/Aperture_(mollusc)" title="Aperture (mollusc)">aperture</a> of the shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the <a href="/wiki/Aperture_(mollusc)" title="Aperture (mollusc)">aperture</a> of the shell and it serves to seal the entrance of the shell. </p><p>Many families have opercula that are reduced in size, and which are not capable of closing the shell aperture. Opercula have sometimes been modified: in the <a href="/wiki/Strombidae" title="Strombidae">Strombidae</a> the operculum is claw-shaped and is used to push into the substrate in a leaping form of locomotion. </p><p>Virtually all <a href="/wiki/Pulmonate" class="mw-redirect" title="Pulmonate">pulmonate</a> snails are inoperculate, i.e. they do not have an operculum, with the exception of the <a href="/wiki/Amphiboloidea" title="Amphiboloidea">Amphiboloidea</a>. However, some <a href="/wiki/Terrestrial_animal" title="Terrestrial animal">terrestrial</a> pulmonate species are capable of secreting an <a href="/wiki/Epiphragm" title="Epiphragm">epiphragm</a>, a temporary structure that can in some cases serve some of the same functions as an operculum. The epiphragm may be distinguished from the true operculum by its homogeneity and want of growth marks. </p><p>In <a href="/wiki/Ammonite" class="mw-redirect" title="Ammonite">ammonites</a> (extinct shelled cephalopods), a calcareous structure known as the <a href="/wiki/Aptychus" title="Aptychus">aptychus</a> (plural aptychi) existed. When these were first described they were thought to be <a href="/wiki/Valve_(mollusc)" title="Valve (mollusc)">valves</a> of a <a href="/wiki/Bivalve" class="mw-redirect" title="Bivalve">bivalve</a> species, then for many years after that they were considered to be a form of paired or single operculum-like structures belonging to ammonites. More recently the aptychus or paired aptychi have been hypothesized to be a <a href="/wiki/Jaw" title="Jaw">jaw</a> apparatus of ammonites. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Functions">Functions</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Operculum_(gastropod)&action=edit&section=1" title="Edit section: Functions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Perhaps the most essential function of the operculum in gastropods is to allow snails to resist drying out, or <a href="/wiki/Desiccation" title="Desiccation">desiccation</a>. This is very important in intertidal marine snails during low tide, and this also enables operculate freshwater and land snails to survive periods of drought and dry weather.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p><p>In those marine species where the operculum completely seals the shell, it can also serve as a protection against <a href="/wiki/Predator" class="mw-redirect" title="Predator">predators</a> when the snail body is retracted.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading2"><h2 id="Anatomy">Anatomy</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Operculum_(gastropod)&action=edit&section=2" title="Edit section: Anatomy"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Penion_sulcatus_live3.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Penion_sulcatus_live3.jpg/220px-Penion_sulcatus_live3.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Penion_sulcatus_live3.jpg/330px-Penion_sulcatus_live3.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Penion_sulcatus_live3.jpg/440px-Penion_sulcatus_live3.jpg 2x" data-file-width="1600" data-file-height="1200" /></a><figcaption><i><a href="/wiki/Penion_sulcatus" title="Penion sulcatus">Penion sulcatus</a></i> near Goat Island, New Zealand, with a damaged operculum</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Bithynia_tentaculata.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c1/Bithynia_tentaculata.jpg/220px-Bithynia_tentaculata.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c1/Bithynia_tentaculata.jpg/330px-Bithynia_tentaculata.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c1/Bithynia_tentaculata.jpg/440px-Bithynia_tentaculata.jpg 2x" data-file-width="719" data-file-height="539" /></a><figcaption>A photo of an individual of the freshwater snail species <i><a href="/wiki/Bithynia_tentaculata" title="Bithynia tentaculata">Bithynia tentaculata</a></i> showing how the back of the shell rests on the round operculum on top of the foot as the snail moves along</figcaption></figure> <p>In life, the operculum is attached at the ending of the <a href="/wiki/Columella_(gastropod)" title="Columella (gastropod)">columellar</a> muscle with an opercular disc dorsally to the upper surface of the posterior part of the foot. However, in <i><a href="/wiki/Buccinum" title="Buccinum">Buccinum</a></i> a layer of long cylindrical <a href="/wiki/Epithelial_cell" class="mw-redirect" title="Epithelial cell">epithelial cells</a>, with mostly distinct nuclei, and long divided processes enter between the muscular fibres. The operculum, a cuticular development of these cells, is composed, as may be seen in the corneous opercula of <i><a href="/wiki/Murex" title="Murex">Murex</a></i>, <i><a href="/wiki/Purpura_(gastropod)" title="Purpura (gastropod)">Purpura</a></i>, <i><a href="/wiki/Triton_(gastropod)" class="mw-redirect" title="Triton (gastropod)">Triton</a></i>, of very thin superimposed layers. The cylindrical cells are attached with their head to the lowermost layer.<sup id="cite_ref-Tryon_1-0" class="reference"><a href="#cite_note-Tryon-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>The operculum grows in size as the shell grows, such that the operculum remains in proportion to the <a href="/wiki/Aperture_(mollusc)" title="Aperture (mollusc)">apertural</a> size. In many species, when the animal is active and crawling, part of the underside of the shell rests on the outer surface of the operculum.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p><p>In many species of marine shelled snails which live subtidally, the operculum is greatly reduced in size, and no longer serves to seal the shell entrance. In a large number of families it has been eliminated completely.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p><p>In species of <a href="/wiki/Conch" title="Conch">conchs</a>, the operculum is elongated and sickle-shaped, and is used to dig into the sand to enable the conch to perform a leaping type of <a href="/wiki/Animal_locomotion" title="Animal locomotion">locomotion</a>.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:FMIB_48688_Various_forms_of_opercula.jpeg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f2/FMIB_48688_Various_forms_of_opercula.jpeg/220px-FMIB_48688_Various_forms_of_opercula.jpeg" decoding="async" width="220" height="54" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f2/FMIB_48688_Various_forms_of_opercula.jpeg/330px-FMIB_48688_Various_forms_of_opercula.jpeg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f2/FMIB_48688_Various_forms_of_opercula.jpeg/440px-FMIB_48688_Various_forms_of_opercula.jpeg 2x" data-file-width="859" data-file-height="211" /></a><figcaption>Various forms of opercula in Pyrula; Purpura; Littorina; Aulopoma; Torinia; Neritopsis; Strombus; Conus </figcaption></figure> <p>The structure of the operculum can be described as follows:<sup id="cite_ref-Tryon_1-1" class="reference"><a href="#cite_note-Tryon-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <ul><li>concentric: the nucleus is central or subcentral as in <i><a href="/wiki/Lithoglyphus" title="Lithoglyphus">Lithoglyphus</a></i> and <i><a href="/wiki/Ampullaria" class="mw-redirect" title="Ampullaria">Ampullaria</a></i>, and in other the nucleus is near the parietal margin of the shell.</li> <li>imbricated, or lamellar: when it grows only on one side, and the nucleus is marginal, as in <i>Purpura</i>,<i> <a href="/wiki/Xenophora" title="Xenophora">Xenophora</a></i>, and <i><a href="/wiki/Paludomus" title="Paludomus">Paludomus</a></i>.</li> <li>claw-shaped, or unguiculate: with the nucleus apical or in front, as in <i><a href="/wiki/Turbinella" title="Turbinella">Turbinella</a></i> and <i><a href="/wiki/Fusus" title="Fusus">Fusus</a></i>; it is claw-shaped and serrated in <i><a href="/wiki/Strombus" title="Strombus">Strombus</a></i></li> <li>spiral: when it grows only on one edge, and revolves as it grows; it is always sinistral in dextral shells.</li> <li>paucispiral or oligogyrous: with few spirals as in <i><a href="/wiki/Littorina" title="Littorina">Littorina</a></i>.</li> <li>subspiral or scarcely spiral, in <i><a href="/wiki/Thiara_(gastropod)" class="mw-redirect" title="Thiara (gastropod)">Thiara</a></i></li> <li>multispiral or polygyrous: having many closely spaced spirals as in <i><a href="/wiki/Trochus" title="Trochus">Trochus</a></i> where they sometimes amount to twenty; the number of turns which the operculum makes is <i>not</i> determined by the number of whorls in the shell, but by the curvature of the aperture, and the necessity that the operculum should revolve fast enough to fit it constantly.</li> <li>articulated, when it has a projection, as in <i><a href="/wiki/Nerita" title="Nerita">Nerita</a></i></li> <li>radiated is a modification of the articulated operculum in which the spiral is not so evident as in <i><a href="/w/index.php?title=Navicella_(gastropod)&action=edit&redlink=1" class="new" title="Navicella (gastropod) (page does not exist)">Navicella</a></i></li></ul> <ul class="gallery mw-gallery-traditional"> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:Filopaludina_martensi_operculum.png" class="mw-file-description" title="Example of a concentric operculum (Filopaludina martensi)"><img alt="Example of a concentric operculum (Filopaludina martensi)" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/06/Filopaludina_martensi_operculum.png/106px-Filopaludina_martensi_operculum.png" decoding="async" width="106" height="120" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/06/Filopaludina_martensi_operculum.png/160px-Filopaludina_martensi_operculum.png 1.5x, //upload.wikimedia.org/wikipedia/commons/0/06/Filopaludina_martensi_operculum.png 2x" data-file-width="190" data-file-height="214" /></a></span></div> <div class="gallerytext">Example of a concentric operculum (<i><a href="/wiki/Filopaludina_martensi" title="Filopaludina martensi">Filopaludina martensi</a></i>)</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:Marstonia_comalensis_operculum.png" class="mw-file-description" title="Example of a polygyrous spiral with eccentric nucleus in the operculum of Marstonia comalensis, scale bar: 200 μm"><img alt="Example of a polygyrous spiral with eccentric nucleus in the operculum of Marstonia comalensis, scale bar: 200 μm" src="//upload.wikimedia.org/wikipedia/commons/thumb/7/72/Marstonia_comalensis_operculum.png/83px-Marstonia_comalensis_operculum.png" decoding="async" width="83" height="120" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/72/Marstonia_comalensis_operculum.png/125px-Marstonia_comalensis_operculum.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/72/Marstonia_comalensis_operculum.png/166px-Marstonia_comalensis_operculum.png 2x" data-file-width="380" data-file-height="548" /></a></span></div> <div class="gallerytext">Example of a polygyrous spiral with eccentric nucleus in the operculum of <i><a href="/wiki/Marstonia_comalensis" title="Marstonia comalensis">Marstonia comalensis</a></i>, scale bar: 200 μm</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:Cremnoconchus_syhadrensis_operculum_2.png" class="mw-file-description" title="Example of an oligogyrous spiral in Cremnoconchus syhadrensis"><img alt="Example of an oligogyrous spiral in Cremnoconchus syhadrensis" src="//upload.wikimedia.org/wikipedia/commons/thumb/5/59/Cremnoconchus_syhadrensis_operculum_2.png/98px-Cremnoconchus_syhadrensis_operculum_2.png" decoding="async" width="98" height="120" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/5/59/Cremnoconchus_syhadrensis_operculum_2.png 1.5x" data-file-width="118" data-file-height="144" /></a></span></div> <div class="gallerytext">Example of an oligogyrous spiral in <i><a href="/wiki/Cremnoconchus_syhadrensis" title="Cremnoconchus syhadrensis">Cremnoconchus syhadrensis</a></i></div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:Opercula_coral_reef_Pliocene_Cyprus.jpg" class="mw-file-description" title="Fossil spiral opercula (both sides) from the Pliocene of Cyprus"><img alt="Fossil spiral opercula (both sides) from the Pliocene of Cyprus" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d5/Opercula_coral_reef_Pliocene_Cyprus.jpg/120px-Opercula_coral_reef_Pliocene_Cyprus.jpg" decoding="async" width="120" height="73" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d5/Opercula_coral_reef_Pliocene_Cyprus.jpg/180px-Opercula_coral_reef_Pliocene_Cyprus.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d5/Opercula_coral_reef_Pliocene_Cyprus.jpg/240px-Opercula_coral_reef_Pliocene_Cyprus.jpg 2x" data-file-width="2483" data-file-height="1516" /></a></span></div> <div class="gallerytext">Fossil spiral opercula (both sides) from the Pliocene of Cyprus</div> </li> </ul> <p>In 1998 Checa and Jimeneze proposed three types of opercula:<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p> <ul><li>type 1: flexiclaudent spiral (mostly multispiral) operculum; its shape does not coincide with the aperture but fits by flexing into the aperture; predominantly present in archaeogastropods.</li> <li>type 2: rigiclaudent spiral (usually paucispiral) operculum; its shape fitting the aperture; present in archaeogastropods, but predominating in Caenogastropoda.</li> <li>type 3: rigiclaudent concentric operculum; its shape fitting the aperture; predominant in higher neotaenioglossans and exclusive in neogastropods.</li></ul> <p>There are two basic types of opercula in terms of their material composition: </p> <ul><li>The most common kind of operculum is composed of a thin to rather thick corneous protein material, which is yellow to brownish in color and is usually somewhat translucent. This matter is supple when in its natural state but may become brittle when it is dried out. The operculum varies in shape, depending on the family of snails and the shape of the aperture of their shells.</li></ul> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Tropidofora_fimbriata_haemostoma_IleRonde_8605.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/e/e5/Tropidofora_fimbriata_haemostoma_IleRonde_8605.jpg" decoding="async" width="125" height="123" class="mw-file-element" data-file-width="125" data-file-height="123" /></a><figcaption>An individual of the land snail <i><a href="/wiki/Tropidophora_fimbriata" title="Tropidophora fimbriata">Tropidophora fimbriata haemostoma</a></i> showing the <a href="/wiki/Calcareous" title="Calcareous">calcareous</a> operculum</figcaption></figure> <ul><li>The other kind of operculum is restricted to a few families of gastropods including the <a href="/wiki/Turbinidae" title="Turbinidae">Turbinidae</a>. This operculum structure has a corneous base with a heavy <a href="/wiki/Calcareous" title="Calcareous">calcareous</a> overlay. The calcareous surface in some genera has color or ornamentation of various kinds including, for example, pustules and incised grooves.</li></ul> <p>The different shapes of opercula can include ungulate (hooflike), claw-like, or ovate. The type and shape of the operculum is used to help identify and classify related groups (genera) of land operculates, and likewise some marine operculates.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading2"><h2 id="Human_uses">Human uses</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Operculum_(gastropod)&action=edit&section=3" title="Edit section: Human uses"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The oldest known human depiction of an operculum together with the shell of <i><a href="/wiki/Charonia_tritonis" title="Charonia tritonis">Charonia tritonis</a></i> is a <a href="/wiki/Seal_(emblem)" title="Seal (emblem)">seal</a> made by the <a href="/wiki/Minoan_civilization" title="Minoan civilization">Minoan civilization</a>.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="As_incense_material">As incense material</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Operculum_(gastropod)&action=edit&section=4" title="Edit section: As incense material"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Opercula of certain <a href="/wiki/Gastropods" class="mw-redirect" title="Gastropods">gastropods</a>, especially varieties from the <a href="/wiki/Red_Sea" title="Red Sea">Red Sea</a>, have long served as an <a href="/wiki/Incense" title="Incense">incense</a> material in ancient <a href="/wiki/Jew" class="mw-redirect" title="Jew">Jewish</a> tradition, as well as <a href="/wiki/Arabian" class="mw-redirect" title="Arabian">Arabian</a> cultures. The operculum of conch species <i><a href="/wiki/Strombus" title="Strombus">Strombus tricornis</a></i> and <i><a href="/wiki/Lambis_truncata" title="Lambis truncata">Lambis truncata</a> sebae</i> are most commonly used in regions near the <a href="/wiki/Middle_East" title="Middle East">Middle East</a>. Opercula from these conches may be the <a href="/wiki/Onycha" title="Onycha">onycha</a> incense material which is described in the <a href="/wiki/Book_of_Exodus" title="Book of Exodus">Book of Exodus</a>.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p><p>Operculum powder is also an important ingredient in <a href="/wiki/China" title="China">Chinese</a> and <a href="/wiki/Japan" title="Japan">Japanese</a> incense making. Here it is called "<i>bèi xiāng</i>" (Chinese: 貝香; <i>lit.</i> sea shell fragrance) or "<i>kai kou</i>" (Japanese: 甲香, <i>lit.</i> shell/armour fragrance) respectively. Incense producers in these countries use the operculum of many conches and other marine <a href="/wiki/Snail" title="Snail">snails</a>, including those found in Southeast Asia, South America, and East Africa. The opercula are traditionally treated with <a href="/wiki/Vinegar" title="Vinegar">vinegar</a>, <a href="/wiki/Ethanol" title="Ethanol">alcohol</a> and <a href="/wiki/Water" title="Water">water</a> in order to remove any <a href="/wiki/Fish" title="Fish">fishy</a> smell. The clean opercula are then ground to a powder and used as a scent fixative, in a technique similar to that used in <a href="/wiki/Perfume" title="Perfume">perfumes</a> with certain plant <a href="/wiki/Resin" title="Resin">resins</a>.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p><p>When burnt on its own, high quality operculum reportedly smells of <a href="/wiki/Castoreum" title="Castoreum">castoreum</a> or other animal <a href="/wiki/Musk" title="Musk">musks</a>, while that of lower quality is reminiscent of burnt hair.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading3"><h3 id="As_a_gemstone_or_decorative_object">As a gemstone or decorative object</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Operculum_(gastropod)&action=edit&section=5" title="Edit section: As a gemstone or decorative object"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The operculum of certain species of <a href="/wiki/Turbinidae" title="Turbinidae">Turbinidae</a> is sometimes used as a very inexpensive organic "<a href="/wiki/Gemstone" title="Gemstone">gemstone</a>" in rings, bracelets, amulets etc. These opercula are commonly known as "cats eye" (or more recently "Shiva's eye").<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p><p>The turban snail <i><a href="/wiki/Turbo_petholatus" title="Turbo petholatus">Turbo petholatus</a></i> is the species whose operculum is most renowned, although other <i>Turbo</i> species are also used. The operculum has two sides of differing appearance. Either side or both may be displayed as jewelry or ornament. The internal side is flat and white, with a spiral suture line, while the external side is hemispherical, glossy, and variously colored and patterned. In the case of <i>T. petholatus</i> there is a prominent dark 'eye' and sometimes a greenish area. </p><p>Opercula are often used in <a href="/wiki/Northwest_Coast_art" title="Northwest Coast art">Northwest Coast art</a> of North America, as detailing in masks, panels and paddles. These objects are used to represent the teeth in masks, and are used as a decorative element in many of the objects which play an important part in the art and culture of Northwest Coast peoples, including dishes for food, bentwood boxes, and rattles.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p><p><a href="/wiki/Friedrich_Ratzel" title="Friedrich Ratzel">Friedrich Ratzel</a> in <i>The History of Mankind</i><sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> reported in 1896 that, in <a href="/wiki/Oceania" title="Oceania">Oceania</a>, chains and girdles composed of the coloured opercula of certain shells were considered valuable ornaments.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2021)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading3"><h3 id="As_paperweights">As paperweights</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Operculum_(gastropod)&action=edit&section=6" title="Edit section: As paperweights"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The largest opercula of <i><a href="/wiki/Turbo_marmoratus" title="Turbo marmoratus">Turbo marmoratus</a></i> have been used as <a href="/wiki/Paperweight" title="Paperweight">paperweights</a>.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Operculum_(gastropod)&action=edit&section=7" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-Tryon-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-Tryon_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Tryon_1-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFTryon_G._W.1882" class="citation book cs1"><a href="/wiki/George_Washington_Tryon" title="George Washington Tryon">Tryon G. W.</a> (1882). <a rel="nofollow" class="external text" href="https://archive.org/stream/structuralandsy00tryogoog#page/n60/mode/2up"><i>Structural and systematic conchology</i></a>. Philadelphia, The author. pp. 47–48.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Structural+and+systematic+conchology&rft.pages=47-48&rft.pub=Philadelphia%2C+The+author&rft.date=1882&rft.au=Tryon+G.+W.&rft_id=https%3A%2F%2Farchive.org%2Fstream%2Fstructuralandsy00tryogoog%23page%2Fn60%2Fmode%2F2up&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOperculum+%28gastropod%29" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChecaJiménez-Jiménez1998" class="citation journal cs1">Checa, Antonio G.; Jiménez-Jiménez, Antonio P. (1998). "Constructional Morphology, Origin, and Evolution of the Gastropod Operculum". <i><a href="/wiki/Paleobiology_(journal)" title="Paleobiology (journal)">Paleobiology</a></i>. <b>24</b> (1): 109–132. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1998Pbio...24..109C">1998Pbio...24..109C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1017%2FS0094837300020005">10.1017/S0094837300020005</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:88680117">88680117</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Paleobiology&rft.atitle=Constructional+Morphology%2C+Origin%2C+and+Evolution+of+the+Gastropod+Operculum&rft.volume=24&rft.issue=1&rft.pages=109-132&rft.date=1998&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A88680117%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1017%2FS0094837300020005&rft_id=info%3Abibcode%2F1998Pbio...24..109C&rft.aulast=Checa&rft.aufirst=Antonio+G.&rft.au=Jim%C3%A9nez-Jim%C3%A9nez%2C+Antonio+P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOperculum+%28gastropod%29" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchifko_G.2005" class="citation book cs1">Schifko G. (2005). <a rel="nofollow" class="external text" href="http://www.biologiezentrum.at/pdf_frei_remote/ANNA_106B_0027-0033.pdf"><i>Zoologische Anmerkungen zu zwei minoischen Siegelabdrücken mit einem Tritonshorn (Gattung </i>Charonia<i>) als Motiv</i></a> <span class="cs1-format">(PDF)</span>. pp. 27–33.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Zoologische+Anmerkungen+zu+zwei+minoischen+Siegelabdr%C3%BCcken+mit+einem+Tritonshorn+%28Gattung+Charonia%29+als+Motiv.&rft.pages=27-33&rft.date=2005&rft.au=Schifko+G.&rft_id=http%3A%2F%2Fwww.biologiezentrum.at%2Fpdf_frei_remote%2FANNA_106B_0027-0033.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOperculum+%28gastropod%29" class="Z3988"></span> <span class="cs1-visible-error citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_book" title="Template:Cite book">cite book</a>}}</code>: </span><span class="cs1-visible-error citation-comment"><code class="cs1-code">|work=</code> ignored (<a href="/wiki/Help:CS1_errors#periodical_ignored" title="Help:CS1 errors">help</a>)</span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRatzel_F1896" class="citation book cs1">Ratzel F (1896). <a rel="nofollow" class="external text" href="http://www.inquirewithin.biz/history/american_pacific/oceania/oceania-labour.htm#ornaments"><i>The History of Mankind</i></a>. <a href="/wiki/London" title="London">London</a>: <a href="/wiki/Macmillan_Publishers" title="Macmillan Publishers">MacMillan</a><span class="reference-accessdate">. Retrieved <span class="nowrap">November 28,</span> 2009</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+History+of+Mankind&rft.place=London&rft.pub=MacMillan&rft.date=1896&rft.au=Ratzel+F&rft_id=http%3A%2F%2Fwww.inquirewithin.biz%2Fhistory%2Famerican_pacific%2Foceania%2Foceania-labour.htm%23ornaments&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOperculum+%28gastropod%29" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.manandmollusc.net/operculum_paul.html">"Operculata"</a>. manandmollusc.net<span class="reference-accessdate">. Retrieved <span class="nowrap">9 July</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Operculata&rft.pub=manandmollusc.net&rft_id=http%3A%2F%2Fwww.manandmollusc.net%2Foperculum_paul.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOperculum+%28gastropod%29" class="Z3988"></span></span> </li> </ol></div></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBurnie,_D2001" class="citation book cs1">Burnie, D (2001). <i><a href="/wiki/Animal_(book)" title="Animal (book)">Animal: The Definitive Visual Guide to the World's Wildlife</a></i>. <a href="/wiki/DK_Publishing" class="mw-redirect" title="DK Publishing">DK Adult Publishing</a>. p. 24.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Animal%3A+The+Definitive+Visual+Guide+to+the+World%27s+Wildlife&rft.pages=24&rft.pub=DK+Adult+Publishing&rft.date=2001&rft.au=Burnie%2C+D&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOperculum+%28gastropod%29" class="Z3988"></span></li></ul> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Operculum_(gastropod)&action=edit&section=8" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Commons-logo.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png" decoding="async" width="30" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/45px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/59px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></a></span></div> <div class="side-box-text plainlist">Wikimedia Commons has media related to <span style="font-weight: bold; font-style: italic;"><a href="https://commons.wikimedia.org/wiki/Category:Operculum_(gastropods)" class="extiw" title="commons:Category:Operculum (gastropods)">Operculum (gastropods)</a></span>.</div></div> </div> <ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20101026224116/http://www.nansaidh.us/operc/index1.html">Pictures of diverse gastropod opercula</a>. This site also provides fairly extensive material on the growth, development, and physiology of the gastropod operculum as well as dozens of pictures of both the operculum and its host shell.</li> <li>Photo of opercula of some <i><a href="/wiki/Busycon" title="Busycon">Busycon</a></i> and <i><a href="/wiki/Busycotypus" title="Busycotypus">Busycotypus</a></i> species</li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol 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href="/wiki/Special:EditPage/Template:Gastropod_anatomy" title="Special:EditPage/Template:Gastropod anatomy"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Gastropod_anatomy" style="font-size:114%;margin:0 4em"><a href="/wiki/Gastropoda" title="Gastropoda">Gastropod</a> anatomy</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Gastropod_shell" title="Gastropod shell">Shell</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0;padding: 0.25em 0; line-height: 1.4em;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Aperture_(mollusc)" title="Aperture (mollusc)">Aperture</a></li> <li><a href="/wiki/Apex_(mollusc)" title="Apex (mollusc)">Apex</a></li> <li><a href="/wiki/Body_whorl" title="Body whorl">Body whorl</a></li> <li><a href="/wiki/Callus_(mollusc)" title="Callus (mollusc)">Callus</a></li> <li><a href="/wiki/Columella_(gastropod)" title="Columella (gastropod)">Columella</a></li> <li><a href="/wiki/Lip_(gastropod)" title="Lip (gastropod)">Lip</a></li> <li><a href="/wiki/Lira_(mollusc)" title="Lira (mollusc)">Lira</a></li> <li><a href="/wiki/Nacre" title="Nacre">Nacre</a></li> <li><a href="/wiki/Periostracum" title="Periostracum">Periostracum</a></li> <li><a href="/wiki/Peristome" title="Peristome">Peristome</a></li> <li><a href="/wiki/Planispiral" title="Planispiral">Planispiral</a></li> <li><a href="/wiki/Plait_(gastropod)" title="Plait (gastropod)">Plait</a></li> <li><a href="/wiki/Protoconch" title="Protoconch">Protoconch</a></li> <li><a href="/wiki/Sculpture_(mollusc)" title="Sculpture (mollusc)">Sculpture</a></li> <li><a href="/wiki/Selenizone" title="Selenizone">Selenizone</a></li> <li><a href="/wiki/Siphonal_canal" title="Siphonal canal">Siphonal canal</a></li> <li><a href="/wiki/Siphonal_notch" title="Siphonal notch">Siphonal notch</a></li> <li><a href="/wiki/Spire_(mollusc)" title="Spire (mollusc)">Spire</a></li> <li><a href="/wiki/Stromboid_notch" title="Stromboid notch">Stromboid notch</a></li> <li><a href="/wiki/Suture_(anatomy)" title="Suture (anatomy)">Suture</a></li> <li><a href="/wiki/Umbilicus_(mollusc)" title="Umbilicus (mollusc)">Umbilicus</a></li> <li><a href="/wiki/Valve_(mollusc)" title="Valve (mollusc)">Valve</a></li> <li><a href="/wiki/Varix_(mollusc)" title="Varix (mollusc)">Varix</a></li> <li><a href="/wiki/Whorl_(mollusc)" title="Whorl (mollusc)">Whorl</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other hard parts</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0;padding: 0.25em 0; line-height: 1.4em;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Clausilium" title="Clausilium">Clausilium</a></li> <li><a href="/wiki/Love_dart" title="Love dart">Love dart</a></li> <li><a class="mw-selflink selflink">Operculum</a></li> <li><a href="/wiki/Pearl" title="Pearl">Pearl</a></li> <li><a href="/wiki/Radula" title="Radula">Radula</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">External soft parts</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0;padding: 0.25em 0; line-height: 1.4em;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Caryophyllidia" title="Caryophyllidia">Caryophyllidia</a></li> <li><a href="/wiki/Caudal_mucous_pit" title="Caudal mucous pit">Caudal mucous pit</a></li> <li><a href="/wiki/Cerata" title="Cerata">Cerata</a></li> <li><a href="/wiki/Cnidosac" title="Cnidosac">Cnidosac</a></li> <li><a href="/wiki/Mantle_(mollusc)" title="Mantle (mollusc)">Mantle</a></li> <li><a href="/wiki/Mentum" title="Mentum">Mentum</a></li> <li><a href="/wiki/Notum" title="Notum">Notum</a></li> <li><a href="/wiki/Parapodium" title="Parapodium">Parapodium</a></li> <li><a href="/wiki/Pneumostome" title="Pneumostome">Pneumostome</a></li> <li><a href="/wiki/Rhinophore" title="Rhinophore">Rhinophore</a></li> <li><a href="/wiki/Semper%27s_organ" title="Semper's organ">Semper's organ</a></li> <li><a href="/wiki/Siphon_(mollusc)" title="Siphon (mollusc)">Siphon</a></li> <li><a href="/wiki/Suprapedal_gland" title="Suprapedal gland">Suprapedal gland</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Internal soft parts</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0;padding: 0.25em 0; line-height: 1.4em;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Circulatory_system_of_gastropods" title="Circulatory system of gastropods">Circulatory system of gastropods</a></li> <li><a href="/wiki/Crop_(anatomy)" title="Crop (anatomy)">Crop</a></li> <li><a href="/wiki/Ctenidium_(mollusc)" title="Ctenidium (mollusc)">Ctenidium</a></li> <li><a href="/wiki/Digestive_system_of_gastropods" title="Digestive system of gastropods">Digestive system of gastropods</a></li> <li><a href="/wiki/Diverticulum_(mollusc)" class="mw-redirect" title="Diverticulum (mollusc)">Diverticula</a></li> <li><a href="/wiki/Excretory_system_of_gastropods" title="Excretory system of gastropods">Excretory system of gastropods</a></li> <li><a href="/wiki/Gastric_shield" title="Gastric shield">Gastric shield</a></li> <li><a href="/wiki/Hancock%27s_organ" title="Hancock's organ">Hancock's organ</a></li> <li><a href="/wiki/Hepatopancreas" title="Hepatopancreas">Hepatopancreas</a></li> <li><a href="/wiki/Hypobranchial_gland" title="Hypobranchial gland">Hypobranchial gland</a></li> <li><a href="/wiki/Nephridium" title="Nephridium">Nephridium</a></li> <li><a href="/wiki/Nervous_system_of_gastropods" title="Nervous system of gastropods">Nervous system of gastropods</a></li> <li><a href="/wiki/Nidamental_gland" title="Nidamental gland">Nidamental gland</a></li> <li><a href="/wiki/Odontophore" title="Odontophore">Odontophore</a></li> <li><a href="/wiki/Oesophageal_pouch" title="Oesophageal pouch">Oesophageal pouch</a></li> <li><a href="/wiki/Osphradium" title="Osphradium">Osphradium</a></li> <li><a href="/wiki/Reproductive_system_of_gastropods" title="Reproductive system of gastropods">Reproductive system of gastropods</a></li> <li><a href="/wiki/Respiratory_system_of_gastropods" title="Respiratory system of gastropods">Respiratory system of gastropods</a></li> <li><a href="/wiki/Sensory_organs_of_gastropods" title="Sensory organs of gastropods">Sensory organs of gastropods</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0;padding: 0.25em 0; line-height: 1.4em;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Epiphragm" title="Epiphragm">Epiphragm</a></li> <li><a href="/wiki/Pseudofeces" title="Pseudofeces">Pseudofeces</a></li> <li><a href="/wiki/Torsion_(gastropod)" title="Torsion (gastropod)">Torsion</a></li> <li><a href="/wiki/Circumesophageal_nerve_ring" title="Circumesophageal nerve ring">Circumesophageal nerve ring</a></li> <li><a href="/wiki/Trochophore" title="Trochophore">Trochophore</a></li> <li><a href="/wiki/Tyrian_purple" title="Tyrian purple">Tyrian purple</a></li> <li><a href="/wiki/Veliger" title="Veliger">Veliger</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=0" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Operculum_(gastropod)&oldid=1258219787">https://en.wikipedia.org/w/index.php?title=Operculum_(gastropod)&oldid=1258219787</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a 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